For all I know, software is uncountable, so it's perfectly fine to say "there is various software". If you don't like how that sounds (I know many people who don't), you can always go with "there are various software packages", "there are various pieces of software" or something like that. An even simpler alternative would be "programs". Depending on the context of your sample sentence, even "video converters" might work, if it's already clear that you are talking about software.
Edit: I have checked Merriam-Webster, Wiktionary and The Free Dictionary, and none of them mentions "softwares"mention softwares at all.